In a system for controlling axis movement of a robot having a plurality of movable axes, acceleration and deceleration control is generally effected so as not to impose shocks and vibration on a mechanical system when starting and stopping the axis movement.
There has been developed in recent years a horizontally articulated robot having a plurality of arms that are angularly movable in horizontal planes, for use in work where many jobs are carried out in horizontal planes, such as for assembling semiconductors or installing electronic parts on printed-circuit boards. The horizontally articulated robot is basically constructed of a first swing arm mounted on the distal end of a post erected on a bed fixed to a floor, the first swing arm being angularly movable horizontally, a second swing arm having one end swingably attached to the distal end of the first swing arm, the second swing arm being angularly movable horizontally, and a wrist mounted on the distal end of the second swing arm. When an object to be moved is gripped by the wrist of the horizontally articulated robot and the swing arms are angularly moved, acceleration and deceleration of a servomotor are controlled initial and final periods of angular movement of the swing arms for smoothly turning the swing arms.
The conventional system for controlling acceleration and deceleration of a horizontally articulated robot having a plurality of arms that are angularly movable in horizontal planes, has a drive source which can produce a torque great enough to move the object in a position remotest from the center of rotation of the arms. In the conventional control system, even when the object is located more closely to the center of rotation of the arms than the remotest position, the object has been moved at the same low acceleration as that when the object is located in the remotest position. Therefore, the time required to move the object is long and the ability of the drive source is not sufficiently utilized.